1. Field of Invention
The present invention relates to a parts feed apparatus equipped in an assembling line, and more particularly to an apparatus for feeding engine valves to valve handling means such as an industrial robot hand by which the engine valve is picked up and fitted or assembled to a cylinder head of a vehicle engine.
2. Prior Art
Various apparatus have heretofore been used to feed engine valves to valve handling or valve fitting means by which the engine valve is held and fitted or inserted into a valve guide of a cylinder head of a vehicle engine. One of such apparatus is disclosed in, for example, Japanese Unexamined Patent Publication No. 62-15,032 entitled "Apparatus For Inserting Valve Into Valve Guide Of Engine Cylinder Head" laid open Jan. 23, 1987. This apparatus is constructed to hold a plurality of engine valves upside down, namely with their valve heads upside, in barrel-shaped holders arranged side by side in a line for feeding them one after another. According to the apparatus above noted, although a plurality of engine valves can be fed at a time, nevertheless, the number of engine valves fed at a time are limited to a relatively low number due to the side-by-side arrangement of the barrel shaped holders. This leads to an inefficient supply of engine valves.
In an attempt at overcoming the limitation of the supply number of engine valves supplied or fed at once, an engine valve supply apparatus has been proposed in an application for Japanese Utility Model Registration Serial No. 61-140,831 filed on Sept. 12, 1986 by the assignee to whom this application was assigned, to improve the efficiency of the supply number of engine valves. This engine valve feeder includes upper and lower hanger plates, each being formed with a plurality of hanger holes in which valve stems of a plurality of engine valves are inserted and held upside down. The respective engine valves are picked up by an industrial robot hand with fingers located above a valve feed station in the assembling line in such a manner as to clamp the engine valve at its joint of valve head with the fingers.
A problem in association with the engine valve feeder is that, due to the adaptation of the robot hand to clamp the joint of valve head, the clamped engine valve is apt to shake while being transferred to a valve fitting station and there being fitted to a cylinder head. Such a shake of the engine valve makes it difficult to insert smoothly the engine valve into the cylinder head, in particular a valve guide fitted to the cylinder head.
If the robot hand clamps the stem of engine valve the engine valve will be prevented from shaking and be smoothly fitted to the valve guide of the cylinder head consequently. In order to allow the robot hand to hold clamping the stem of engine valve, it is necessary to protrude the engine valve up from the hanger plate. This, however, may result in another problem if the engine valve protruded up inclines with respect to the hanger plate and is thereby out of position for being clamped at the stem thereof by the robot hand.